A fracture is a complete or incomplete break in a bone resulting from the application of excessive force. An injury may be classified as a fracture-dislocation when a fracture involves the bony structures of any joint with associated dislocation of the same joint.
Fractures are also named by the specific portion of the bone involved and the nature of the break. The identification of the fracture line can further classify fractures. Types include linear, oblique, transverse, longitudinal, and spiral fractures. Fractures can be further subdivided by the positions of bony fragments and are described as comminuted, non-displaced, impacted, overriding, angulated, displaced, avulsed, and segmental.
Immobilization refers to the process of holding a joint or bone in place with a splint, cast, or brace. This is done to prevent an injured area from moving while it heals. All known apparatuses and processes for operations associated with connection of broken bones require the use of devices for immobilization, support and fixation of the broken bones or their parts. Supporting and fixing devices are needed for securing the broken parts of the bones together in connecting the bones through intramedullary nailing, extramedullary plates, as well as when there are chances for the broken bones to grow together naturally.
Intramedullary nailing or fixation is a method for holding a fractured bone in proper alignment by means of a metal pin or nail in the marrow cavity. This is normally performed by means of a steel spike inserted through the medually canal of a tubular bone to provide internal immobilization of fractures. Usually, intramedullary nailing fixation is utilized when there are no chances for the broken bones to grow together naturally.
In the opinion of specialists, for weight-bearing bones, intramedullary nailing is a fixation method superior to plates or external fixation, because the location of the rod in the intramedullary canal virtually guarantees proper axial alignment. Properly applied, an intramedullary fixation holds a fracture so securely that the patient can begin to move at once. It is an important factor, because, as is known, with early movements the fracture diseases (such as stiffness and edema) are abolished. Other advantages of the intramedullary fixation are precise reduction and immediate stability of the fractured bones.
But in spite of all the advantages of the intramedullary fixation, this method is used seldom and surgeons try to avoid the use of this method. This is because the intramedullary fixation requires a very accurate axial alignment of fractured bone parts, i.e., an accurate alignment of holes for the insertion of the intramedullary nail into the bone parts to be interconnected.
In accordance with conventional practice such a drilling has to be performed with the aid of an X-ray apparatus for locating the precise position of the hole of the intramedullary nail before the drilling operation is started. In any case, it is extremely difficult to ensure strictly coaxial position of the holes in both parts of the broken bones, and the applicant is not aware of any efficient devices which are on the market and which could provide an efficient and reliable axial alignment of holes in mating parts of the broken bone.
U.S. Pat. No. 5,833,691 granted to the same applicant in 1998 discloses a device for coaxially drilling holes in fractured bones for intramedullary fixation, which consists of a frame supporting a first V-shaped support for a first part of a fractured bone and a second V-shaped support for a second part of the fractured bone. The V-shaped supports are spaced from each other. The apparatus has a drilling head with a calibrated pin at the rear side of the drilling head. The drilling head is alternatingly installed in the aforementioned V-shaped supports for drilling coaxial and strictly aligned holes in both parts of the fractured bone. The calibrated pin has the same diameter as the drill bit of the drilling head and is intended for insertion into the bone hole, which is drilled first in order to support and align the drilling head with the second part of the bone during drilling of the second hole. In operation, the surgeon supports the drilling head with one hand and performs the feed of the bone toward the drill with another hand.
A main disadvantage of the aforementioned device is a significant weight which does not allow to keep this device for fixation of the bones over the entire period of healing, i.e., until the bone parts grow together naturally or during intramedullary connection. The known construction is not only heavy but also inconvenient for use by the operation-room personnel. Furthermore, the device has a complicated design, which cannot be easily produced in small dimensions. The device of the aforementioned patent may have a limited practical application for connection mainly of femur bones and is not suitable for intramedullary connection of clavicle, humerus, radius, ulna, fibula, tibia, and other thin bones. Movement of the drill during formation of holes in the bones is complicated and inefficient. Furthermore, the known apparatus is not versatile and cannot be left in place after fixation of the bone for natural growing together in view of its heavy weight and large dimensions.
The method claimed in the aforementioned U.S. Pat. No. 5,833,691 also has a number of disadvantages, the main of which is that for drilling of the hole in the second part of the broken bone, it was necessary to insert the tail shaft of the drill head into the hole previously drilled in the bone. This is extremely undesired operation as it will load the broken bone with an additional weight. The second problem is that the second part of the bone should be pulled toward the rotating drill bit.
Furthermore, the known device cannot be attached to the bone parts and remain attached to the bone till complete healing. This is because the entire device should rest onto a support surface.